Fuse



Fell 20, 1934. J. LE R. JOHNSON Er AL 1,948,421

FUSE

Filed NOV. 22, 1952 Patented Feb. 20, 1934 UNITED STATES FUSE Justus Le Roy Johnson, Lynwood, and Martin Geiszler, South Gate, Calif.

Application November 22, 1932 Serial No. 643,941

1 Claim.

This invention relates to improvement-s in fuses and has particular referenceto a fuse and fuse block wherein it is impossible to bridge the fuse plug when the same .is blown out or to bridge the fuse block without employing a peculiarly formed fuse plug.

A further object is to produce a device which will conform to ordinary electrical regulations and by utilizing the standard Edison screw base and shell to produce a non-bridgeable fuse plug that can be used in present type installations.

A further object is to produce a device which is economical to manufacture.

A further object is to produce a device wherein the standard practice of screwing a fuse into a receptacle is maintained.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawing forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same,

Fig. l is a cross sectional view of my fuse,

Fig. 2 is a cross sectional view of my fuse in a fuse block,

Fig. 3 is a top plan view of the fuse plug engagn ing member, and

Fig. 4 is a side elevation of Fig. 3.

Fuses are inserted in electric lines for the purpose of providing a safety factor should too much current be drawn from the line, the fuse melting before the wires of the line can become over-heated. With the ordinary fuse now in use and particularly with the fuse block it is often possible to bridge over a burned-out fuse`or the fuse block, thus re-establishing the electrical connection. Such objects as pieces of wire, pennies and the like are commonly employed for this purpose. As soon as this is done, a hazard is introduced for the reason that the fusible element has been replaced by a non-fusible element. Applicants have devised a construction wherein these objections have been eliminated.

In the accompanying drawing wherein for the purpose of illustration is shown a preferred embodiment of our invention, the numeral 5 designates the base of a fuse block upon which is mounted through the medium of a screw 6, a conductor 7 to which the line Wire 8 is secured. This conductor 7 has an upwardly bent portion 9 provided with a tongue 11. Also mounted upon the base 5 .is a bus bar l2 held to the base by a screw 13. To this bus bar is connected a wire 14 which is really a continuation of the wire 8. A block of insulating material 16 is mounted (Cl. 20G- 119) upon the base 5 and serves to support an insulating piece 17 having an annular projection 18. Positioned within the block 16 and confined by the insulating piece 17, is a spring-pressed pin 19. The spring 21 serves to normally maintain @0 a collar 22 against the bottom of the recess formed on the underside of the insulating piece 17. Mounted upon the base 5 and enclosing the block 16 and insulating piece 17 is a cover plate 22. This cover plate has an upstanding por tion 23 within which is mounted a fuse engaging member 2a. This fuse engaging member consists of a metal shell having a thread and an outwardly bent flange 26. This flange 26 has springs 27 struck therefrom and adapted to engage a shoulder 28' formed upon the cover block 22. The springs are so formed that they normally tend to hold the fuse engaging member pressed downwardly against the block 16, that is, when the fuse has been removed. '[5 Referring now to Fig. l, the fuse is of the usual general configuration commonly employed for this purpose and consists of an insulating mernbei 30 having a metal shell 29 provided with screw threads to engage the threads of the fuse engaging element 24. This shell holds a bushing 31 to the member 30, which bushing has a projection 32 through which projection runs a pin 33 the upper end being connected to one end of a fuse wire 34. This fuse wire is preferm g5 ably passed through openings 36 and 37 of an insulating member 38 so as to lie beneath a window 39.' The opposite end of this fuse wire is connected to the shell 29.

The manner of using our device is as follows: Assuming that the fuse as a whole has been removed from the fuse block, the result will be l that the springs 27 'will have forced the shell 24 downwardly against the block 16 and therefore will have moved the flange 26 out of contact with 95 the end l1 of the conductor 7. At the same time the spring 21 will have forced the pin 19 upwardly and therefore the lower end of the pin will be out of contact with the bus bar 12. Therefore, it would be impossible for a person to insert their fingers or any instrument into the fuse block and complete a connection or get a' shock therefrom. However, by screwing my fuse as a whole, into the fuse block the threads of the shell 29 will engage the threads of the shell 105 24 and when the fuse is screwed down tightly the metallic bottom end of the pin 33 at theend of the projection 32 will push downwardly upon the pin 19 forcing the same against the bus bar 12 and at the same time pulling upwardly on the nl, op

shell 24 against the tension of the springs 27, thus moving the flange 26 into Contact with the end il of the conductor 7. The current will then ow from the wire 8 through the conductor to the ange 26 of the shell 24, thence through the shell 29 to the fuse wire, thence through the fuse wire to the pin 33, through the pin 19 to the bus bar l2 and to the wire 14. It will be apparent thatwhen the fuse burns out, it will be impossible to insert a new wire in the fuse or a metal connection in the fuse block. Therefore, we have provided a safety fuse which will perform all the objects above set lorth.

lt is to be understood that'the form of our invention herewith shown and described is to be taken as a preferred example of the same and that various changes relative to the material, size, shape and arrangement of parts majT be resorted to without departing from the spirit of the invention or the scope of the subjoined claiL-n Having thus described our invention, we claim:-

1n a device of the character described, adapted to cooperate with an electrical fixture having an upstanding annular projection and a threaded element, of an insulating member and a bushing mounted therein, a threaded member connecting said insulating member and said bushing, said bushing having an annular tapered recess, a projection formed on said bushing and centrally located with respect to said annular recess, the end of said projection extending beyond the plane of the end of said bushing, a pin extending through said projection, and means for completing an electric circuit between said threaded member and said pin.

JUSTUS LE ROY JOHNSON. MARTIN GEISZLER. 

